<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="../css/index.css">
</head>
<body>
<!--
   穷举法
   1 2 3   √
   1 - 3 2 √
   2 1 - 3 √
   2 3 1   √
   3- 1 2  √
   3 2 1   √

-->
<div class="box-container">

    <div class="left">
        <div class="box right">1</div>
        <div class="box left">2</div>
    </div>

    <div class="box left">3</div>
</div>

</body>
</html>